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.APPLE PRODUCTS INFORMATION PKG. 



ORIGINATOR: Larry Sovulewski 
DATE: 6-Aug-82 



£cippkz computer inc. 



POWER SUPPLY SCHEMATICS AND COMPONENT LAYMTS 



Apple J I — 

Astec AA11040 ....... 1 

Astec AA11040/B ......... 3 

Apple /// 

Astec AA11190 .• 5 

Profile /// — 

Astec AA11770 7 

Astec AA11770/A 9 

Astec AA11771 10 

POWER SUPPLY COMPONENT LISTINGS 



Apple J I — 

Astec AA11040 12 

Astec AA11040/B ...... 14 

Apple /// — 

Astec AA11190 17 

Profile /// ~ 

Astec AA11770 21 

Astec AA11770/A 25 

Astec AA11771 26 

Astec - Apple Part # Cross Reference «.... 32 

POWER SUPPLY INFORMATION 



Astec "Notes On Power Supplies" ••••• 34 

"Switching Power Supplies" 56 

-i- 



r 



PLEASE NOTE 



ASTEC Services, Ltd. may provide a suitable replacement with 
a different part number, depending on vendor availability. Also, 
not all ASTEC component parts are available from Apple Computer 
at this time. As of this release, we are in the process of ob- 
taining piece part listings and costs to be entered onto the MIS 
Corporate system. When this has been done, all Service Sites will 
receive updated parts cross-reference listings and additional 
parts ordering information. The present cross-reference listing 
included in this package lists about 40% of the parts by Apple 
Part Number. 



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R14 R1SR19R20 R21C17R22R23C18R24R25CO 



STEC #AA11Q4Q-B 



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APPLE III 



A8TEC #AA1119Q 




PROFILE III 



ASTEC #AA1177Q 




MONITOR BOARD - ASTEC #AA11770/A 
PROFILE 



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© 1981 ASTCC COMPONENTS LTO MADE IN HONG KONG 



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lONG KONG ^ L * vJ/»22A2e ^ j£ 



III 



ASTEC #AA1 1771 



ASTEC 11040 STANDARD POWER SUPPLY 



-12- 



LOCATION 


DESCRIPTION 


VENDOR NO. 


CI 


POLYESTER CAPACITOR 0.1 UF 400V 


058-10400100 


C2 


ELECTROLYTIC CAPACITOR 47 UP 250V 


057-47020040 


C3 


ELECTROYLTIC CAPACITOR 47 UF 250V 


057-47020040 


C4 


ELECTROYLTIC CAPACITOR 47 UF 250V 


057-47020040 


C5 


ELECTROYLTIC CAPACITOR 47 UF 250V 


057-47020040 


C6 


TANTALUM CAPACITOR 22 UF 16V 


072-22600040 


C7 


CERAMIC CAPACITOR 1000 PF 3KV 


055-10210001 


C8 


CERAMIC CAPACITOR 0.01 UF 1KV 


055-10367325 


C9 


ELECTROYLITIC CAPACITOR 1000 UF 10V 


057-10220020 


CIO 


ELECTROYLITIC CAPACITOR 1000 UF 10V 


057-10220020 


Cll 


ELECTROYLITIC CAPACITOR 330 UF 16V 


057-33120080 


ulZ 


EL&CTROYL1TIC CAPACITOR ZZO UF 10V 


05/— ZZlZUUoO 


C13 


ELECTROYLITIC CAPACITOR 1000 UF 10V 


057-10220020 


C14 


POLYESTER CAPACITOR 1000 PF 50V 


058-10200020 


C15 


ELECTROYLITIC CAPACITOR 1000 UF 10V 


057-10220020 


C16 


ELECTROYLITIC CAPACITOR 220 UF 10V 


057-22120060 


C17 


ELECTROYLITIC CAPACITOR 680 UF 16V 


057-68120010 


C18 


ELECTROYLITIC CAPACITOR 330 UF 16V 


057-33120080 


Dl 


RECTIFIER RPG10M 


226-10400050 


02 


SILICON DIODE 1N4150 


212-10700050 


D3 


RECTIFIER RGP10M 


226-10400100 


DA 


RECTIFIER/HEATSINK ASSEMBLY 


853-00200020 




ttFlTTFTErP /TTSP ATCTMIT ACCVUHTV 




D6 


RECTIFIER/HEATSINK ASSEMBLY 


853-00200020 


n7 
uf 


KJSuTlrlEK RGrljB 


ZZO— 10 100040 


D8 


RECTIFIER RGP10B 


226-10400070 


no 


SILICON DIODE 1N4150 


*% ^ A7 AAACA 

Z1Z— 10/00050 


D10 


SILICON DIODE 1N4150 


212-10700050 


Dll 


BLANK 




DB1 


BRIDGE RECTIFIER KRP10 


226-30500010 


£ JL 


FTT W 7 7 S AMP 7 ^ft WYT 




LI 


CONTROL CHOKE COIL 


328-00150016 


L2 


FILTER CHOKE COIL ASSEMBLY 


TF-20100010 


L3 


FILTER CHOKE COIL ASSEMBLY 


TF-20100050 


T A 


FILTER CHOKE COIL ASSEMBLY 


i«m im AAA1A 


L5 


FILTER CHOKE COIL ASSEMBLY 


TF-20100020 


Ql 


TRANSISTOR NPN PE8050 


209-11700382 


Q2 


TRANSISTOR NPN 2SC1358 


209-10200020 


Q3 


TRANSISTOR NPN PE8050 


209-11700382 


04 


TRANSISTOR PNP PE8550 


210-11700322 


Rl 


THERMISTER 4R @25 DEG.CEN +-10Z 


258-40970015 


R2 


RESISTOR CARBON FILM 2.2M +-5Z 


240-22506033 



COMPONENT LISTING - ASTEC AA11040 



-13- 



R3 


RESISTOR 


CARBON 


FILM 


2.2M +-52 


240-22506033 


R4 


RESISTOR 


CARBON 


FILM 82R +-52 


240-82006033 


R5 


RESISTOR 


METAL OXIDE 


FILM 27R 


248-27006052 


R6 


RESISTOR 


CARBON 


FILM 


4.7R +-52 


240-47906033 


R7 


RESISTOR 


CARBON 


FILM 


10R +-52 


240-10006022 


R8 


RESISTOR 


METAL FILM 0.33R +-5Z 


247-03386054 


R9 


RESISTOR 


CARBON 


FILM 


180R +-52 


240-18106022 


RIO 


RESISTOR 


CARBON 


FILM 


12R +-52 


240-12006022 


Rll 


RESISTOR 


CARBON 


FILM 


470R +-52 


240-47106022 


RI2 


RESISTOR 


CARBON 


FILM 


IK +-52 


240-10206022 


R13 


BLANK 










R14 


RESISTOR 


CARBON 


FILM 


IK +-52 


240-10206022 


R15 


RESISTOR 


CARBON 


FILM 


330R +-52 


240-33106022 


R16 


RESISTOR 


CARBON 


FILM 


5.6K +-52 


240-56206022 


AX / 


RESISTOR 


CARBON 


FILM 


27R +-52 


240-27006022 

fctv mm 1 \J\J\J \J mm mm 


R18 


RESISTOR 


CARBON 


FILM 


82R +-52 


240-82006033 




RESISTOR 


CARBON 


FILM 


IK +-52 


240-10206022 

*»**W X \J mm\J \f \J mm mm 


R20 


RESISTOR 


CARBON 


FILM 


2.7K +-52 


240-27206022 


R21 


BLANK 










R22 


RESISTOR 


CARBON 


FILM 


100R +-52 


240-10106033 


R23 


RESISTOR 


CARBON 


FILM 


100R +-52 


240-10106033 


R24 


RESISTOR 


CARBON 


FILM 


390R +-52 


240-39106022 




SILICON CONTROL 


RECTIFIER 2P 05M 


227—1 2Sonoio 

mm mm 1 L mm J KJ\J\J ±,\J 


Tl 


POWER TRANSFORMER ASSEMBLY 


TF-10200370 


T2 


CONTROL TRANSFORMER ASSEMBLY 


TF-10200200 


T3 


COMMON MODE TRANSFORMER ASSEMBLY 


TF-20200010 


Zl 


ZENER DIODE 12.2V 4-0. 2V 


222-12295001 


Z2 


ZENER DIODE 6.8V +-0.2V 


222-06895003 


VDR1 


VARISTOR 


260VAC 






256-26100014 



PCB 



PRINTED CIRCUIT BOARD (NO PART'S) 



042-02012202 



CASE 
CASE 
CASE 



SWITCH (ROCKER TYPE) 

AC IMPUT SOCKET (THREE PRONG GROUND) 

VOLTAGE SELECTION SWITCH 115/230 



278-01200020 
149-00200010 
283-02200100 



(CASE) 
(CASE) 



BOTTOM PLATE 1.6 AL SHEET 
COVER (TOP) 1.6 AL SHEET 



403-03100700 
403-03100810 



— \ 

-14- 



ASTEC POWER SUPPLY AA11040B 



LOCATION 


DESCRIPTION 


VENDOR HO. 


CI 


MP CAP 0.1 OF +-20Z 250 VAC 


068-19100010 


C3 


CER CAP 2200 PF +-20Z 400 VAC 


055-22100010 


C4 


CER CAP 2200 PF +-20Z 400 VAC 


055-22120001 


C5 


ELEC CAP 47 OF +100-10Z 250V 


057-41820040 


C6 


ELEC CAP 47 UF +100-10Z 250V 


057-43320040 


C7 


ELEC CAP 220 UF +50 -10Z 10V 


057-2220080 


C8 


CER CAP 47 PF +-20Z 3KV 250 


055-4B67728 


C9 


CER CAP 0.01 UF +-20Z 1KV 25U 


055-l»58925 


CIO 


CER CAP 0.01 UF +-20Z 1KV 25V 


055-l®58925 


Cll 


POLY CAP 0.22 UF +-10Z 100V 


058-23*00120 


C12 


ELEC CAP 1000 UF +100 -10Z 10V 


057-1M20020 


C13 


ELEC CAP 1000 UF +100 -10Z 10V 


057-13H20020 




Ft VC TAP 1 OOfl TTF +1 00 —1 OI 1 fW 


0S7— 1*70020 


C15 


ELEC CAP 220 UF +100 -10Z 10V 


057-22120060 


C16 


ELEC CAP 220 UF +100 -10Z 10V 


057-2S20060 


CI 7 


POLY CAP 0.022 UF +-20Z 100V 


058-22300080 


C18 


POLY CAP 0.22 UF +-10Z 100V 


058-23100120 


C19 


ELEC CAP 1000 UF +100 -10Z 10V 


057-1020020 


C20 


ELEC CAP 580 UF +100 -10Z 16V 


057-6®20010 


C21 


ELEC CAP 330 UF +100 -10Z 16V 


057-33120080 


C22 


ELEC CAP 330 UF +100 -10Z 16V 


057-33120080 


C23 


CER CAP 0.01 UF +-20Z 1KV 25U 


055-l®68925 


C24 


ELEC CAP 47 UF +100 -10Z 250V 


057-4H20040 


C25 


ELEC CAP 47 UF +10 -10Z 250V 


057-4H20040 


1/1 






D2 


RECTIFIER RPG10M 


225-18100100 


D3 


RECTIFIER RPG10M 


226-19100100 


D4 


SILICON DIODE 1N4606 


212-I®00210 




^tt Trnw nTnriP in£.aoa 


4LL4L Lmm%f\J 4m JL\J 


D6 


RECTIFIER ASSY 


853-OH00210 


n7 


BT?PTTWTT?B AQ^V 
JxCUlXf JLJ&Iv aDDI 


fis 4 ^— (mtoo2io 


D8 


RECTIFIER ASSY 


853-OK00210 


D9 


RECTIFIER RGPA5B 


226-1S00040 


DIO 


RECTIFER RGP158 


226-11100070 


Dll 


SILICON DIODE 1N4606 


212-1SPQ0210 


D12 


RECTI IER RGP158 


225-1H00040 


DB1 


BRIDGE RECTIFIER KBP10 


225-31500010 


Fl 


FUSE 2.75A 125V 


084-OW00040 


ICI 


IC TL431CP/TL431CLP 


211-1000100 


LI 


CHOKE COIL ASSY 


852-2H00140 


L2 


CHOKE COIL ASSY 


852-2MO0140 


L3 


BASE CHOKE 2.2 Ufl 


328-GH00030 


L4 


CHOKE 1.5 MH (PROPRIETARY) 


328-0® 00010 


L5 


CHOKE COIL ASSY 


852-l«)0370 




-15- 



COMPONENT LISTING - ASTEC AA11040B 



L6 
L7 
L8 

Ql 

Ql 
Q2 

Q3 
Q3 
Q4 

Rl 

R2 

R3 

R4 

R5 

R6 

R7 

R8 

R9 

RIO 

Rll 

R12 

R13 

R14 

R15 

RI6 

R17 

R18 

R19 

R20 

R21 

R22 

R23 

R24 

R25 

R26 

R27 

R28 

R29 

R30 

R31 



CHOKE COIL ASSY 
CHOKE COIL 
CHOKE COIL 

NPN TRANSISTOR 
NPN TRANSISTOR 
NPN TRANSISTOR 
PNP TRANSISTOR 
PNP TRANSISTOR 
PNP TRANSISTOR 



2SD592NC 
2SD467C 
2SC1875 
2SB621NC 
2SB561C 
2SB62INC 



THERMISTOR 4R +-10Z OR 5R 
RESISTOR METAL FILM 150K +-52 1/2 W 
RESISTOR METAL FILM 150K +-5Z 1/2 W 
RESISTOR METAL OXY FILM 27R +-5Z 2 W 
RESISTOR CARBON FILM IK -»— 5Z 1/2 W 
RESISTOR CARBON FILM 27R +-5Z 1/2 W 
RESISTOR CARBON FILM +-5Z 1/4W 68R 
RESISTOR METAL OXY FILM 120R +-5Z 1W 
RESISTOR CARBON FILM 8.2R +-5Z 1/4 W 
RESISTOR CARBON FILM 10R +-5Z 1/4 W 
RESISTOR METAL FILM 0.56 +-5Z 1W 
RESISTOR CARBON FILM 68R+-5Z 1/4W 
RESISTOR CARBON FILM 270R +-5Z 1/2W 
RESISTOR CARBON FIM D270R +-5Z 1/2W 
RESISTOR CARBON FILM 8.2R +-5Z 1/2W 
RESISTOR CARBON FILM 390R +-5Z 1/4W 
RESISTOR CARBON FILM 22R +-5Z 1/2W 
RESISTOR CARBON FILM 100R +-5Z 1/4W 
RESISTOR CARBON FILM +-5Z 1/4W 56R 

1/2W 
1/4W 

RESISTOR CARBON FILM 470R +-5Z 1/4W 
RESISTOR METAL FILM 2.7K +-2Z 1/4W 
RESISTOR METAL FILM 2.7K +-2Z 1/4W 
RESISTOR CARBON FILM 100K +-5Z 1/4W 
RESISTOR CARBON FILM 680R +-5Z 1/4W 
RESISTOR CARBON FILM 1.8K +-5Z 1/4W 
RESISTOR METAL FILM +-5Z 1W 1R 
RESISTOR METAL FILM +-5Z 1/4W 32R 
RESISTOR METAL OXY FILM 220R +-5Z 1W 
RESISTOR CARBON FILM 224 4-5Z 1/4W 



RESISTOR CARBON FILM 56R +-5Z 
RESISTOR CARBON FILM 12K +-5Z 



SCR1 SCR C1220/2N695 

Tl COMMON MODE TRANSFORMER ASSY 

T2 POWER TRANSFORMER ASSY 

T3 POWER TRANSFORMER ASSY (SUB) 

Zl ZENER DIODE 9.8V +-0.2V (2K7) 

VDR1 VDR 260 VAC 

CASE VOLTAGE SELECTION SWITCH 115/230V 



328-20100010 
852-10100490 
852-10100490 

209-11700400 
209-11700460 

209- 10200030 
210 11700330 

210- 11700350 
210-11700330 

258-40970015 
240-15406033 
240-15406033 
248-27006063 
240-10206022 
240-27006022 
240-68006022 
248-12106052 
240-82906022 
240-10006022 
247-05686054 
240-68006022 
240-27106033 
240-27106033 
240-39106022 
240-39106022 
240-22006022 
240-10106022 
240-56006022 
240-56006022 
240-12306022 
224-27106022 
247-27015022 
247-27015022 
240-10406022 
240-68106022 
240-18206022 

247- 10086-54 
240-82006033 

248- 22106052 
240-22006022 

227-13000010 

852-20200950 
852-10200940 
852-10200680 

222-98085002 

256-26100014 

283-02200100 



£cippkz computer inc. 



-16- 

COMPONENT LISTING - ASTEC AA11040B 



CASE SWITCH ROCKER 278-01200020 

CASE AC INPUT SOCKET 149-00200010 

CASE BOTTOM PLATE 1.6 AL SHEET 403-03100700 

CASE COVER (TOP) 1.6 AL SHEET 403-03100810 




COMPONENT LISTING - ASTEC AA11190 -17- 

CODE DESCRIPTION PART NUMBER 

BRl Bridge rectifier KBPlO 226-30500010 

Cl Metallized paper cap 0.22uF 250VIC 068-22400010 

C2 Metallized paper cap O.luF 250VJC 068-10400010 

C3 Ceramic cap 4700pF 400VAC 055-47220001 

C4 Ceramic cap 4700pF 400VAC 055-47220001 

C5 Polyester cap O.luF 400V 058-10400100 

C6 Electrolytic cap lOOuF 250V 057-10120170 

C7 Electrolytic cap lOOuF 250V 057-10120170 

C8 Electrolytic cap lOOuF 250V 057-10120170 

C9 Electrolytic cap lOOuF 250V 057-10120170 

CIO Electrolytic cap 220uF 10V 057-22120080 

Cll Ceramic cap O.OOluF 3KV 055-10261328 

C12 Polyester, cap 0.22uF 100V 058-22400120 

C13 Electrolytic cap lOOOuF 10V 057-10220020 

C14 Electrolytic cap lOOOuF 10V 057-10220020 

C15 Electrolytic cap lOOOuF 10V 057-10220020 

C16 Electrolytic cap lOOOuF 10V 057-10220020 

C17 Electrolytic cap 330uF 16V 057-33120080 

C18 Electrolytic cap 22ouF 10V 057-22120060 

C19 Polyester cap 0.022uF 100V * 058-22300080 

C20 Electrolytic cap lOOOuF 10V 057-10220020 

C21 Polyester cap 0.22uF 100V 058-22400120 

C22 Electrolytic cap lOOOuF 10V 057-10220020 

C23 Electrolytic cap 330uF 16V. 057-33120080 

C24 Electrolytic cap 680uF 16V 057-68120010 

C25 Electrolytic cap 330uF 16V 057-33120080 

C26 Ceramic cap 0.1/lKV 055-10360925 

Dl Rectifier RGPlOA 226-10400050 

D2 Rectifier RGPlOM 226-10400100 

D3 Rectifier RGPlOM 226-10400100 

D4 Rectifier 1N4001GP 226-10400080 

D5 Silicon diode 1N5282 212-10700200 



^cippkz computer inc. 



COMPONENT LISTING - ASTEC AA11190 -18- 

CODE DESCRIPTION PART NUMBER 

D6 Silicon diode 1N5282 212-10700200 

D7 Rectifier / SCR assembly 853-00700010 

D8 Rectifier assembly 853-00200140 

D9 Rectifier assembly 853-00200140 

D10 Rectifier assembly 853-00200140 

Dll Schottky diode S3SC3M 212-31100030 

D12 Rectifier RG3B 226-10700010 

D13 Silicon diode 1N5282 212-10700200 

Fl Fuse 2.75A 125V 084-00200040 

IC1 Regulator TL431CP 211-10800070 

Jl Jumper wire 358-80810011 

Jumper wire 358-80810011 

J3 Jumper wire 358-80810011 

J4 Jumper wire 358-80810011 

J5 Jumper wire 358-80800001 

LI choke 852-20100350 

L2 Choke 852-20100350 

L3 Base choke 328-00100030 

L4 Choke 1.5mH • 328-00100010 

1*5 Choke coil assembyy 852-20100010 

L6 Choke coil 852-10100370 

L7 Choke coil 328-00100060 

L8 Choke coil 328-00100060 

Q 1 Transistor SD467 209-11700463 

Q2 Transistor 2SC1358 209-10200010 

Q3 Transistor SB561 210-11700353 

Q4 Transistor SB561 210-11700353 



^cippkz computer inc. 



COMPONENT LISTING - ASTEC AA11190 



CODE 


DESCRIPTION 










PART NUMBER 


Rl 


Thermistor 4R @25°C 4 


—10% 






258-40970015 




6R @ 25 "C +-20% 










258-60990010 


R2 


Resistor 


carbon 


film 


150K 


+-5% *sW 




240-15406033 


R3 


Resistor 


carbon 


film 


150K 


+-5% %W 




240-15406033 


R4 


Resistor 


metal oxide 


film 


+-5% 47R 


7m 


248-47006063 


R5 


Resistor 


carbon 


film 


+-5% 


*iW 1.2K 




240-12206022 


R6 


Resistor 


carbon 


film 


5.6R 


+-5% 




240-56906022 


R7 


Resistor 


carbon 


film 


+-5% 


56R fcw 




240-56006022 


R8 


Resistor 


metal oxide 


film 


+-5% 120R 




248-12106063 


R9 


Resistor 


carbon 


film 


+-5% 


**W 15R 




240-15006022 


RIO 


Resistor 


carbon 


film 


+-5% 


VW 10R 




240-10006022 


Rll 


Resistor 


carbon 


film 


+-5% 


*W 15R 




240-15006022 


R12 


Resistor 


metal film 0.47R 






247-04786054 


R13 


Resistor 


carbon 


film 


+-5% 


W 39R 




240-39006022 


R14 


Resistor 


carbon 


film 


+-5% 


270R 




240-27106033 


R15 


Resistor 


carbon 


film 


+-5% 


270R %W 




240-27106033 


R16 


Resistor 


carbon 


film 


8.2R 


+-5% 




240-82906022 


R17 


Resistor 


carbon 


film 


+-5% 


680ft fcW 




240-68106022 


R18 


Resistor 


carbon 


film 


+-5% 


2.7K hW 




240-27206022 












2.2K 




240-22206022 












1.8K 




240-18206022 


R19 


Resistor 


carbon 


film 


+-5% 


560R 




240-56106022 


R20 


Resis.tor 


carbon 


film 


22R +-5% 




240-22006022 


R21 


Resistor 


carbon 


film 


100R 


+-5% 




240-10106022 


R22 


Resistor 


carbon 


film 


56R +-5% >*W 




240-56006022 


R23 


Resistor 


carbon 


film 


56R +-5% 




240-56006022 


R24 


Resistor 


carbon 


film 


12K +-5% 




240-12306022 


R25 


Resistor 


carbon 


film 


+-5% 


htf 470R 




240-47106022 


R26 


Resistor 


metal film +-2% 2.7K **W 




247-27015022 


R27 


Resistor 


metal film +-2% 2.7K 




247-27015022 


R28 


Resistor 


carbon 


film 


100K 


+-5% %W 






R29 


Resistor 


carbon 


film 


100K 


+-2% 




240-10406022 


R30 


Resistor 


metal oxide 


film 


+-5% 56R 


m 


248-56006052 


R31 


Resistor 


metal oxide 


film 


+-5% 220R IW 


248-22106052 



•19- 



£cippkz computer inc. 



r 



CODE 
R32 



COMPONENT LISTING - ASTEC AA11190 
DESCRIPTION 

Resistor metal film lR lw 



PART NUMBER 



247-10086P54 



-20- 



Tl 
T2 
T3 



Common mode choke assembly 
Power transformer assembly 
Control transformer assembly 



852-20200010 
852-10200160 
852-10200680 



VDRl 



Varistor 260 VAC 



256-2610(1114 



Zl 



Zener diode 9.6 to 10. 0V @lmA 



222-98085002. 



^cippte computer inc. 



COMPONENT LISTING - ASTEC AA11770 



LUL'L 


DESCRIPTION 




DaoT MO 


BRl 


Bridge rectifier KBPIO 




226-30500010 


CI 


MP cap O.luF +-20% 250VAC 




068-10400010 


C2 


Cer cap 2200pF +-20% 400VAC 




055-22220001 


C3 


Cer cap 2200pF +-20% 400VAC 




055-22220001 


C4 


MP cap O.luF +-20% 250VAC 




068-10400010 


C5 


Poly cap O.luF +-10% 400V 




058-10400100 


C6 


Elect cap 47uF +100 -10% 250V 




057-47020040 


C7 


Elect cap 47uF +100 -10% 250V 




057-47020040 


C8 


Elect cap 47uF +100 -10% 250V 




057-47020040 


C9 


Elect cap 47uF +100 -10% 250V 




057-47020040 


CIO 


Elect cap 220uF +50 -10% 10V 




057-22120080 


Cll 


Cer cap 470pF +-20% 3KV Z5P 




055-47167728 


C12 


Poly cap 0.22uF +-10% 100V 




058-22400120 


C13 


Elect cap lOOOuF +100 -10% 10V 




057-10220020 


C14 










CI5 


Elect cap lOOOuF +100 -10% 10V 




057-10220020 


C16 


Elect cap 330uF +-20% 16V 




057-33120120 


C17 







_ 


C18 


Poly cap 0.022uF +-20% 100V 




058-22300080 






or 


058-22300090 


C19 


Poly cap 0.22uF +-10% 100V 




058-22400120 


• 




or 


058-22400240 


C20 


Elect cap lOOOuF +50 -10% 25V 




057-10220040 


C21 


Elect cap 470uF +50 -10% 25V 




057-47120110 


C22 


Elect cap 470uF +50 -10% 25V 




057-47120110 


C23 









C24 


Elect cap lOOOuF +100 -10% 10V 




057-10220020 


C25 


Cer cap O.OluF +-20% 1KVZ5U 




055-10368925 


Dl 


Rectifier RGP10B 




226-10400070 


D2 


Rectifier RGP10J 




226-10400060 


D3 


Rectifier RGP10M 




226-10400100 


D4 


Rectifier RGP15B 




226-10100040 



f|cippkz computer inc. 



CODE 



COMPONENT LISTING - ASTEC AA11770 
DESCRIPTION 



PART NO, 



D5 

D6 

D7 

D8 

D9 

D10 

DII 

DI2 

D13 



Rectifier 3S4M 
Silicon diode 1N4606 
Silicon diode 1N4606 
Schottky diode S3SC3M 
Schottky diode S3SC3M 

Rectifier RGP10B 



Silicon diode 1N4606 



226-11400010 
212-10700210 
212-10700210 
212-31100030 
212-31100030 

226-10400070 

212-10700210 



Fl 



Fuse 2.5A 250V 3 AG 



084-00200060 



IC1 
IC2 

Jl 
J2 
J3 
J4 
J5 
J6 
J7 
J8 
J9 



IC TL431CLP 

Jumper wire 10 -2mm 

Jumper wire dia 0.8mm L=3 . 0mm 

Jumper wire 10.2mm 

Jumper wire 10.2mm 

Jumper wire 10.2mm 

Jumper wire dia 0.8mm 



211-10800100 

358-10920011 
358-80810011 
358-10920011 
358-10920011 



358-10920011 



358-80810011 



LI 
L2 
L3 
L4 
L5 
L6 
L7 
L8 



Common mode choke assembly 

Toroid 

Toroid 

Base choke 2.2uH 
Choke 1.5mH 
Choke coil assembly 
Choke coil assembly 
Choke coil assembly 



852-20200120 
124-00000110 
124-00000110 
328-00100030 
328-00100010 
852-20100010 
852-10100370 
852-10100490 



ricippte computer inc. 

wBr CD 



CODE 

Ql 

.Q2 
Q3 

Rl 



R2 

R3 

R4 

R5 

R6 

R7 

R8 

R9 

RIO 

Rll 

R12 

R13 

R14 

R15 

R16 

R17 

R18 

R19 

R20 

R21 

R22 

R23 

R24 

R25 

R26 

R27 



COMPONENT LISTING - ASTEC AA11770 
DESCRIPTION 

NPN transistor SD467 



NPN transistor 2SC1875 
PNP transistor SB56I 



Thermistor 4R +-10% 



Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 
Resistor 



carbon film 150K +-5% *jW 
carbon film 150K +-5% 
metal oxide film 68R +-5% 1W 
carbon film 820R +-5% *jW 
carbon film 5.6R +-5% *xW 
metal oxide film 120R +-5% 1W 
carbon film 5.6R +-5% 
carbon film 47R +-5% hM 
carbon film 10R +-5% 
carbon film 5.6R +-5% 
metal film 0.47R +-5% 1W 
carbon film 39R +-5% 
carbon film 270R +-5% *jW 
carbon film 330R +-5% 
carbon film 8.2R +-5% 
carbon film 330R +-5% 
carbon film 12R +-5% **W 
carbon f^lm 56R +-5% *xW 
carbon film 56R +-5% **W 
carbon film 12K +-5% hW 
carbon film 470R +-5% *aW 



Resistor carbon film 2.2K +-5% »xW 
Trimpot IK +-20% 

Resistor carbon film 2.2K +-5% *aW 
Resistor metal film 1R +-5% 1W 



PART NO . 
209-11700460 
or 209-11700400 

209- 10200030 

210- 11700350 
or 210-11700330 

258-40970015 
or 258-50990010 
or 258-60990010 
240-15406033 
240-15406033 
248-68006052 
240-82106022 
240-56906022 
248-12106052 
240-56906022 
240-47006022 
240-10006022 
240-56906022 
247-04786054 
240-39006022 
240-27106033 
240-33106033 
240-82906022 
240-33106022 . 
240-12006022 
240-56006022 
240-56006022 
240-12306022 
240-47106022 

240-22206022 
254-10280014 
240-22206022 
247-10086054 



^applG computer inc. 



CODE 



R28 



COMPONENT LISTING -. ASTEC Ml 17 70 
DESCRIPTION 



-24- 



PART NO. 



Tl 
T2 



Power transformer ass'y 
Control transformer ass,y 



852-10201210 
852-10200680 



SCR1 



SCR C122U 



227-13000010 



VDR1 



VDR 260VAC 



256-26100014 



I/P connector 
O/P Connector 



Locking header 2cct 
Locking header 12cct 



146-00200490 
146-00200500 



r 



-25- 



CODE 

CI 
C2 
C3 
C4 



COMPONENT LISTING - ASTEC AA11770A 

DESCRIPTION 

Cap Poly 0.22uF 100V 
Cap Ceramic O.OluF 100V 
Cap Tant lOuF 25V 
Cap Tant lOuF 25V 



PART NUMBER 

058-22400120 
055-10382125 
072-10600070 
072-10600070 



Dl 
D2 
D3 



Diode IN4606 
Diode IN4606 
Diode IN4606 



212-10700210 
212-10700210 
212-10700210 



Rl Resistor CF 12K 5% Jw 240-12306022 

R2 Resistor CF 2.7K 5% Jw 240-27206022 

R3 Resistor CF 100R 5% Jw 240-10106022 

R4 Resistor CF 470R 5% $W 240-47106022 

R5 Resistor CF 100K 5% Jw 240-10406022 

R6 Resistor CF 100K 5% £w 240-10406022 

R7 Resistor CF 10K 5% Jw 240-10306022 

R8 Resistor CF 100K 5% Jw 240-10406022 

R9 Resistor CF 100K 5% }W 240-10406022 

RIO Resistor CF 100K 5% Jw 240-10406022 

Rll Resistor CF 47R 5% £w 240-47006022 

R12 Resistor CF 47R 5% Jw 240-47006022 

R13 Resistor CF 2.2K 5% $W 240-22206022 

R14 Resistor CF 470K 5% $W 240-47406022 

R15 Resistor CF 100K 5% Jw 240-10406022 



Ql 
Q2 
Q3 
Q4 

Q101 



2SB561C 
2SD467C 
2SD467C 
2SD467C 
TL431CLP 



210- 11700353 
209-11700463 
209-11700463 
209-11700463 

211- 10800100 



^cippkz computer inc. 



-25a 



COMPONENT LISTING - APPLE MONITOR #656-0104 



CODE 


DESCRIPTION 




APPLE PART # 


CI 


(not used) 








C2 


Capacitor, luF, 20%, 


35v 


048 


127-0001 


n O 

Cj 


Capacitor, 10uF, 20%, 


16 v 


049 


127-0101 


C4 


Capacitor, 10uF, 20%, 


lov 


049 


127-0101 


CR1 


Diode, Zener 5%, 


lOv 


050 


371-5240 


CRZ 


Diode, Switching 1N4150 


50v 


035 


371-4150 


CR3 




J\J V 


035 


371-4150 


Rl 


Resistor 56 ohm l/2w 


5% 


041 


101-2560 


R2 


Resistor 100K ohm Iw 


10% 


042 


107-0023 


R3 


(not used) 








R4 


Resistor 33K ohm l/4w 


5% 


043 


101-4333 


R5 


Resistor 10K ohm l/4w 


5% 


045 


101-4103 


R6 


Resistor 2K ohm l/4w 


5% 


047 


101-4202 


R7 


Resistor 100K ohm l/4w 


5% 


044 


101-4104 


R8 


Resistor 100K ohm l/4w 


5% 


044 


101-4104 


R9 


Resistor 22K ohm l/4w 


5% 


046 


101-4223 


Ql 


Transistor, NPN Sw.& Amp. 


2N3904 


003 


372-3904 


Q2 


Transistor, NPN Sw.& Amp* 


2N3904 


003 


372-3904 



Ul 
U2 



Transistor, NPN Optocoupler 054 327-0011 

Voltage Detector/Indicator, 8 Pin 055 353-8212 



-26- 



CODE - 
BR1 

CI 
C2 

C3 

C4 

C6 

C7 

C8 

C9 

CIO 

Cll 

C12 

C13 

C16 

C18 

C19 

C20 
C21 
C22 
C24 



COMPONENT LISTING - ASTEC AA11771 
DESCRIPTION- 
Bridge rectifier KBP10 

MP cap O.OluF +-20% 250VAC 
Cer cap 2200pF +-20% 400VAC 
MP cap 2200pF +-20% 250VAC 
Cer cap 2200pF+-20% 400VAC 
MP cap 2200pF +-20%~250VAC- 
MP cap O.luF +-20% 250VAC 
Elect cap 47uF +100-10% 250V 
Elect cap 47uF +100-10% 250V 
Elect cap 47uF +100-10% 250V 
Elect cap 47uF +100-10% 250V 
Elect cap 220uF +-20% 10V SXA 
Cer cap 470pF +-20% 3KV Z5P 
Poly cap 0.22uF +-10% 100V 
Elect cap lOOOuF +-20% 16V SXA 
Elect cap lOOuF +-20% 25V SXA 
Poly cap 0.022uF +-20% 100V 

Poly cap 0.22uF +-10% 100V 

Elect cap lOOOuF +-20% 16V SXA 
Elect cap lOOOuF +-20% 16V SXA 
Elect cap lOOuF +-20% 25V SXA 
Elect cap 2200uF +-20% 10V SXA 



PART NUMBER 



226-30500010 



068- 
055- 

or 068- 
055- 

or 068- 
068- 
057- 
057- 
057- 
057- 
057- 
055- 
058- 
057- 
057- 
058- 

or 058- 
058- 

or 058- 
057- 
057- 
057- 
057- 



•10300010 
•22220001 
•22200020 
•22220001 
•22200020 
•10400010 
■47020040 
•47020040 
•47020040 
47020040 
22120300 
47167728 
22400120 
10220180 
10120270 
22300080 
22300090 
22400120 
22400240 
10220180 
10220180 
10120120 
22220120 



-27- 



CODE 

C25 

C26 

C27 

C28 

C29 

C30 

C31 

C32 



COMPONENT LISTING - ASTEC AA11771 
DESCRIPTION 

Cer cap O.OluF +-20% 1KV Z5U 
Cap Poly 0.22uF 100V 
Cap Ceramic v 01uF 100V 
Cap Tant lOuF 25V 
Cap Tant lOuF 25V 
Cer cap 470pF +-107. 100V Z5F 
MP cap O.OluF +-20% 250VAC 
Cap ceramic O.OluF 100V 



PART NUMBER 

055-10368925 

058-22400120 

055-10382125 

072-10600070 

072-10600070 

055-47152126 

068-10300010 

055-10382125 



Dl 

D2 

D3 

D4 

D5 

D6 

D7 

D8 

D9 

Dll 

D13 

D14 

D15 

D16 



Rectifier RGP10B 
Rectifier RGP10J 
Rectifier RGP10M 
Rectifier RGP15B 
Rectifier RGP10B 
Silicon diode 1N4606 
Silicon diode 1N4606 
Schottky diode S3SC3M 
Schottky diode S3SC3M 
Rectifier 3S4M 

Silicon diode 1N4606 
Diode 1N4606 
Diode 1N4606 
Diode 1N4606 



226-10400070 
226-10400060 
226-10400100 
226-10100040 
226-10400070 
212-10700210 
212-10700210 
212-31100030 

212-31100030 
226-11400010 

212-10700210 
212-10700210 
212-10700210 
212-10700210 



tcippkz computer inc. 



r 



CODE 



Fl 



COMPONENT LISTING - ASTEC AA11771 
DESCRIPTION 

Fuse 2.5A 250V 3AG 



-28- 



PART NUMBER. 



084-00200060 



LI 
L2 
L3 
L4 
L5 
L6 
L7 
L8 



Common mode choke assembly 

Toroid 

Toroid 

Base choke 2.2uH 
Choke 1.5mH 
Choke coil assembly 
Choke coil assembly 
Choke coil assembly 



852-20200120 
124-00000110 

r24-ooooono 

328-00100030 
328-00100010 
852-20100180 
852-20100180 
852-10100490 



Ql 

Q2 
Q3 

04 

Q5 
Q6 
Q7 
Q9 

Q101 



NPN transistor SD467 

NPN transistor 2SC1875' 
PNP transistor SB561 

2SB561C 

2SD467C 

2SD467C 

2SD467C 

TL431CLP 

TL431CLP 



209-11700460 
or 209-11700400 

209- 10200030 

210- 11700350 
or 210-11700330 

210- 11700353 
209-11700463 
209-11700463 
209-11700463 

211- 10800100 
211-10800100 



COMPONENT LISTING - ASTEC Mil 771 



-29- 



CODE 


DESCRIPTION . 






PART NUMBER 


Rl 


Thermistor 4R +• 


1 A°7 




ZjO-*rU7/UUlJ 












or Zjo-Du77UUiu 












or -Z3o— 0U77UUIU 


13 O 

Rz 


Resistor 


carbon 


film 


1 AAW ! C»/ T TIT 

1UUK t-O/o 1W 


A'fU-lUHUOUjj 


R3 


Resistor 


carbon 


film 


1UUK +-5/e 1W 


9Aa«iaaaaaqo 

Z^U— iU'rUOU J J 


T> A 

R4 


Resistor 


metal oxide 


C • i r On i c*/ ITT 

film 6oR +-54 lw 


OAQ tflAAAA^O 


t* c 

R5 


Resistor 


carbon 


film 


OOAn t C •/ It i 

820R -f-5/o %}n 


O A A Q01 AtAOO 

Z4U-oZiU0UzZ 


R6 


Resistor 


carbon 


film 


C £- T\ t CO/ \s t 

5 . 6R +-5/o yd 


O A A C£J3AtAOO 

240-5o9UoUZZ 


R7 


Resistor 


metal oxide 


film 120R +-54 lw 


OAQ 1 Ol AtAO 

24o-IzlOoU5Z 


R8 


Resistor 


carbon 


film 


C £ T* 1 CO/ It T 

5 . 6R +-5 /. £W 


O/. A C£.QA£AOO 

z40-5690oUZz 


R9 


Resistor 


carbon 


film 


47R +-57. #J 


O /. A /. "7AA£AOO 

240-4700o0zZ 


RIO 


Resistor 


carbon 


film 


10R +-57. fctf 


O/. A 1AAA£AOO 
24Q-I000602Z 


Rll 


Resistor 


carbon 


film 


5.6R +-57. & 


O A A C£AA£/"\00 

240-56906022 


R12 


Resistor 


metal film 0.47R +-57o 1W 


O A "7 A A "7 O £. A C A 

247-u47obQ54 


R13 


Resistor 


carbon 


film 


39R +-57. 


247-39006022 


R14 


Resistor 


carbon 


film 


270R +-57. %tf 


OA A 0*7TA£AOO 

240-27106033 


R15 


Resistor 


carbon 


film 


330R +-57. $7 


OA A OOIA^AOO 

240-33106033 


Rio 


Resistor 


carbon 


film 


8.2R +-57. £W 


OA A QOOAtAOO 

Z4-U-qZ9UOUZZ 


Rl / 


Resistor 


carbon 


film 


330R +-57. %H 


A A O. 11 A A A 9 
ZhU— jJiUOUZZ 


Rio 


AcS iSlOi 


carbon 


film 


12R +-57. #J 


Z^U— iZUUOUZZ 


R19 


Resistor 


carbon 


film 


56R +-57. toU 


OA A C.£AA£AOO 

Z^U-5oUUoUZZ 


R20 


Resistor 


carbon 


film 


56R +-57. ton 


240-56006022 


R21 


Resistor 


carbon 


film 


12K +-57. to» 


240-12306022 


R22 


Resistor 


carbon 


film 


470R +-57. %W 


240-47106022 


R24 


Resistor 


carbon 


film 


2.7K +-27. J0H 


247-27015022 



-30- 



C0MP0NENT LISTING - ASTEC AA11771 

CODE - DESCRIPTION 

R26 Resistor carbon film 2.7K +-27, %W 

R27 Resistor metal film 1R +-5% 1W 

R28 Resistor CF 12K 5% 

R29 Resistor CF 2.7K 57. 

R30 Resistor CF 100R 57. htf 

R31 Resistor CF 470R 57. 

R32 Resistor CF 100K 57 e 

R33 Resistor CF 100K 57. %A 

R34 Resistor CF 10K 57o k& 

R35 Resistor CF 100K 57. 

R36 Resistor CF 100K 57 iW 

R37 Resistor CF 100K 57 %W 

R38 Resistor CF 56R 57 

R39 Resistor CF 56R 57. %W 

R40 Resistor CF IK 57. #J . 

R41 Resistor CF 100K 57 ^ 

R42 Resistor CF 100K 57o 

R43 Resistor CF 220K 57. £W 

R44 Resistor CF 100K 57o %A 

R45 Resistor CF 220K 57 . 

R46 Resistor CF 10 OK 57, £W 



PART NUMBER 

247-27015022 

247-10086054 

240-12306022 

240-27206022 

240-10106022 

240-47106022 

240-10406022 

240-10406022 

240-10306022 

240-10406022 

240-10406022 

240-10406022 

240-56006022 

240-56006022 

240-10206022 

240-10406022 

240-10406022 

240-22406022 

240-10406022 

240-22406022 

240-10406022 



R48 



Resistor CF 100K 57. iW 



240-10406022 



goppkz computer .nc 



r 



CODE 

Tl 

T2 



COMPONENT LISTING - ASTEC AA11771, 
DESCRIPTION 

Power transformer ass'y 
Control transformer ass'y 



-31- 



P&IT NUMBER 

851- 10201210 

852- 10200680 



SCR1 



SCR C122U 



221-13000010 



VDR1 



Zl 



VDR 260VAC 



Zener 5,6 +5% 1W 40mA 



25i-26100014 
222,- 5 6086002 



^cippla computer inc. 



-32- 



ASTEC - APPLE PART NUMBER CROSS REFERENCE LISTING 
ASTEC PART # DESCRIPTION 



TF- 10200200 

TF- 10200370 

TF-20100010 

TF-20100020 

TF- 20 100050 

TF-20200010 

042-02012202 

055-10210001 

055-10367325 

055-10368925 

055-22220001 

055-47167728 

057-10220020 

057-22120060 

057-22120080 

057-33120080 

057-47020040 

057- 68120010 

058- 10200020 
058-10400100 
058-22300080 
058-22400120 
068-10400010 
072-22600040 
084-00200040 
209-10200020 
209-10200030 
209-11700382 

209- 11700400 

210- 11700322 

210- 11700330 

211- 10800100 

212- 10700210 
222-06895003 
222-12295001 
222-98085002 
226-10100040 
226-10400050 
226-10400070 
226-10400100 

226- 30500010 

227- 12500010 
227-13000010 



Z50,(VDE) 
(VDE) 
Z5P,(VDE) 



CONTROL TRANSFORMER ASSEMBLY 
POWER TRANSFORMER ASSEMBLY 
FILTER CHOKE COIL ASSEMBLY, RADIAL 
FILTER CHOKE COIL ASSEMBLY, RADIAL 
FILTER CHOKE COIL ASSEMBLY, RADIAL 
TRANSFORMER, COMMON MODE ASSEMBLY 
P.C. BOARD (ASTEC 11040 STD.) 
CAPACITOR, CERAMIC DISC, Z5U, 
CERAMIC DISC, 
CERAMIC DISC, 
CERAMIC DISC, 
CERAMIC DISC, 
ELECTRO. ,SW. TYPE, RDL.LD. 
ELECTRO. ,SW.TYPE,RDL.LD. 
ELECTRO., RDL.LD. 
ELECTRO. ,SW. TYPE, RDL.LD. 
ELECTRO. ,SW. TYPE, RDL.LD. 
ELECTRO. ,SW. TYPE, RDL.LD. 
METAL IZED POLY, RDL.LD. 
CAPACITOR, METALIZED POLY, 
CAPACITOR, POLYESTER FILM, 
CAPACITOR, POLYESTER FILM, 
METALIZED POLY, 
TANTALUM, 
FUSE, 2.75A, 125V 
TRANSISTOR, NPN 2SC1358 
NPN 2SC1875 
NPN PE8050 
NPN 2SD592NC/2SD467C 
TRANSISTOR, PNP PE8550 
TRANSISTOR, PNP 2S8621NC/2SB561C 
I.C. .OPTICAL COUPLER, TL431CP/TL43 
DIODE, SILICON, 1N4606 
DIODE, ZENER, 6.8V +/-0.2V 
DIODE, ZENER, 12.2V +/-0.2V 
DIODE, ZENER, 9.8V +/-0.2V 
RECTIFIER, RG15B 

RGP10A (G.I.) 
RGP10B 

RGP10M (G.I.) 
BRIDGE, KBP10 
SCR, 2P 05M 
SCR, C122U/2N6395 



CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 
CAPACITOR, 



CAPACITOR, 
CAPACITOR, 



TRANSISTOR, 
TRANSISTOR, 
TRANSISTOR, 



RDL.LD. 
RDL.LD. 
RDL.LD. 

RDL.LD. 



lOOOpF, 
O.OluF, 
O.OluF, 
2200pF, 
47 pF, 
,1000uF, 
, 220uF, 
, 220uF, 
, 330uF, 
, 47uF, 
, 680uF, 
,1000pF, 
, O.luF, 
,.022uF, 
,0.22uF, 
O.OluF, 
, 22uF, 



1CLP 



(2K7) 



RECTIFIER, 
RECTIFIER, 
RECTIFIER, 
RECTIFIER, 
RECTIFIER, 
RECTIFIER, 





APPLE # 




tti q7.nnn^ 




tti S7— nnnA 

Ul J/ UUU*t 




U133— UUUO 




tti ^— nn i n 
Ul jo— uuiu 




tti e \^— nnno 




tti R7— nnnA 
Ul D /— UUUo 




ttq on nn 1 n 
UoZO— 0010 




tti ^9— nnn^ 


1KV 


U132-0004 

\J X 'J *m V/V/V/"T 


X£V¥ 


U132-0002 

VJ X <J *m V/V/V/ im 


HUU V 


tti ^9— noni 

UX «j£ UUU 1 


JM 


TTI ^1—0001 

UiJl V/V/V/X 


10V 

X V/ v 


Ul 28-0003 


10V 

XV/ w 


U124-0004 

UlAit V/V/V/*T 


10 V 

XV/ W 


Ul 26-0001 

UXfcU V/V/V/X 


16V 

X V# T 


U124-0002 

UX«»*T V/V/V/4. 


250? 


Ul 24-0001 


16V 

X V# T 


Ul 24-0005 


50V 

mt V/ W 


U121-0102 

W X mm X V 1 V A> 


400V 


U121-0101 

UX^l v/xv/x 


100V 

X V/V/ V 


Ul 19— 0002 

UX X 7 V/V/V/*. 


i nnv 

x uu ¥ 


TTI 1 Q— 0001 

U117 V/V/V/X 


250? 


U121-0100 


16V 

X VI w 


U127-0001 

Ul^f V/V/V/X 




U740-0001 

v/~v/ V/V/V/X 




U376-0005 




Uj / O— UUU4 




TTOTfi. nnn/ 
Uo/O— UUU4 




11^76—0001 

UJ / V# UUU X 




UJ/ O UUUO 




itx~7 a— nnn i 




TT^97-.nnm 

UJ£/ — Uuui 




U37 1-0001 




U37 1-0003 




U37 1-0004 




U37 1-0002 




U375-0015 




U375-0014 




U375-0016 




U37 5-0013 




U35 1-0001 




U37 6-0007 




U37 2-0001 



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ASTEC - APPLE PART NUMBER CROSS REFERENCE LISTING 
ASTEC PART # DESCRIPTION 



240-10006022 
240-10106022 
240-10406022 
240-12206022 
240-12306022 
240-15406033 
240-18206022 
240-22206022 
240-27106033 
240-27206022 
240-47106022 
240-56006022 
240-56106022 
240-68106022 
240-82006033 
247-03386054 
247-05686054 

247- 10086054 

248- 12106052 
248-22106052 
248-27006052 
248-27006063 
247-27015022 
256-26100014 
258-40970015 
283-02200100 
328-00100010 
328-00100030 
328-00150016 
328-20100010 
852-10100370 
852-10100490 
852-10200680 
852-10200940 
852-20100140 

852- 20200950 

853- 00200210 
853-00200020 



RESISTOR, CARBON FILM, 4-5% 1/4W 10 OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 100 OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 100K OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 1 .2K OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 12K OHM 

RESISTOR, METAL FILM, 4-5% 1/2W 150K OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 1 .8K OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 2.2K OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 270 OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 2.7K OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 470 OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 56 OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 560 OHM 

RESISTOR, CARBON FILM, 4-5% 1/4W 680 OHM 

RESISTOR, METAL FILM, 4-5% 1/2W 82 OHM 

RESISTOR, METAL FILM, 4-5% 1 W .33 OHM 

RESISTOR, METAL FILM, 4-5% 1 W .56 OHM 

RESISTOR, METAL FILM, 4-5% IV 1 OHM 

RESISTOR, MTL-OX FILM, 4-5% 1 W 120 OHM 

RESISTOR, MTL-OX FILM, 4-5% 1 W 220 OHM 

RESISTOR, MTL-OX FILM, 4-5% 1 W 27 OHM 

RESISTOR, MTL-OX FILM, 4-5% 2 W 27 OHM 

RESISTOR, MTL-OX FILM, 4-2% 1/4W 2.7K OHM 
TRANSIENT SUPPRESSOR, VDR 260VAC 
THERMISTOR, 4R, 10% or 5R 
VOLTAGE SELECTION SWITCH 115/230 
CHOKE, 1.5 mH, RADIAL 
BASE CHOKE, 2.2 uH, RADIAL 
CHOKE COIL, CONTROL, RADIAL 
CHOKE COIL ASSEMBLY, RADIAL 
CHOKE COIL ASSEMBLY, RADIAL 
CHOKE COIL, RADIAL 
CONTROL TRANSFORMER ASSEMBLY 

POWER TRANSFORMER ASSEMBLY 
CHOKE COIL ASSEMBLY, RADIAL 
COMMON MODE TRANSFORMER ASSEMBLY 
RECTIFIER ASSEMBLY 
RECTIFIER, HEATSINK ASSEMBLY 



APPLE # 

U101-4100 
U101-4101 
U101-4104 
U101-4122 

U101-4123 
Ul 07-0001 
U101-4182 
U101-4222 
U10 1-4271 
U101-4272 
Ul 01-4471 
U101-4560 
U101-4561 
U10 1-4681 
Ul 07-0001 
U107-0010 
U107-0004 
U107-0006 
U107-0003 
U107-0008 
U107-0009 
U107-0002 
U107-0005 
U37 7-0001 
U107-0100 
U705-0003 
U155-0003 
U155-0002 
U155-0007 
U155-0005 
Ul 5 5-0004 
U155-0006 
U157-0003 

U157-0002 
Ul 5 5-0001 
Ul 57-0001 
U375-0017 
U375-0018 



£appkz computer inc. 



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With Compliments 




EUROPE LTD 



NOTES ON POWER SUPLIES 



CONTENTS 



1*0 Introduction 

2.0 What's a Power Supply 

3#0 SMPS Basics 

4#0 Advantages & Disadvantages of SMPS 

5*0 Types of SMPS 

6*0 How to read Data Sheets 

Appendix 



ASTEC EUROPE LTD 



November 1981 



ffccippkz computer inc. 



-35- 



1.0 INTRODUCTION 



ASTEC ffisnuf actures flyback and feed- forward , single and 
multi-pail output Power Supplies* 

The Company places a lot of emphasis on the production of 
ultra-reliable power supplies. Special consideration is given to 
thermal criteria durinq the design phase. High temperature (125 
deg C) reverse bias Burn-in for a minimum of 24 hours is standard 
procedure for all cri t ical transistors and diodes. Elimination of 
doubtful components by comparative measurements before and after 
Burn-in prior to their use in assembly contribute to our a&ility 
to ship Power Supplies that will continue to give years of 
satisfactory life* 

Additional information concerning our manufacturing process will 
be found in the Appendix. 

Elec'tro-magnetic disturbances from Switching Mode Power Supplies 
are a potential problem* ASTEC solves these problems and reduces 
both line conducted and radiated radio frequency noise to ieet 
the International performance standards by incorporating 
correctly designee! line filters and electrostatic shielding of 
the power switching transformer. 

In the following pages we will be describing in detail the 
circuit tecniques we use and comparing various types of Power 
Supply solutions. 

A section is devoted to an explanation of how to read and 
interpret our Data Sheets. 



ffcippkz computer inc. 
WT<3> 



-36- 



2.0 WHAT IS A POWER SUPPLY ? 



In essence there are two basic types of regulated power supplies. 
Linear Supplies - series and shunt varieties. 



surplus power 

Switchinq Supplies - buck and boost varieties 

Characterised by using only that part of the 
input power tht is required and hence not dissipating the surplus 
as heat 

(Note:- This fundamental difference is important. AH electronic 
circuits become less reliable at high temperatures* Thus by 
avoiding creating excess heat the switching power supply becomes 
inherent ly bet ter # > 

To look at these varieties in a little more detail 
2»1 Linear supplies. 

A linear regulator absorbs the difference 
between the input voltage at the source and the regulated voltage 
at the load* 



Characterised by dissipating as heat the 



(se«? fig 1) 



dissipation 







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2.2 Switching supplies* 



A switching regulator stores the excess 



power in a LC filter ( a network consisting of an inductor and a 
capacitor ) and delivers the power to the load in measured 
interval s* 

The two basic varieties of switching regulators are:- 
2.2.1 Buck* (see fig 2) 

During the time the switch is ON, energy is stored in the network 
consisting of the inductor L and capacitor C and is delivered to 
the load as required* 

The output voltage of the Buck regulator is controlled by the 
duty cycle of the switch. 



T 

The output voltage may be controlled from zero volts to E in* 



2*2*2 Boost, (see fig 3) 

The Boost regulator is similar to the Buck regulator except that 
the circuit is designed to provide an output voltage that is 
higher than the input voltage* 



E out s t ♦ on 



E in 



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— ^ 

-38- 




SwrtCH 



L 



IN 



Aw 



f5 



COT 



-r . . J 




IN 



Switch 



OUT 



Fig. 3. Switching boost 




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-39- 



3,0 SWITCHING POWER SUPPLIES 



The basic schematic diagram of a Switch Mode Power Supply is 
shown in Figure 4* 

The mode of operation of this power supply is as follows;- 

The AC input from the line is rectified and filtered to obtain a 
DC voltage that has an acceptable ripple content* 

The transistor switch chops the DC voltage into a series of 
rectangular waves which are changed to the required voltage by a 
transformer* The voltage appearing on the secondary of this 
transformer is rectified and filtered to produce the final output 
vol tage(s) required* 

In order to ensure that the output voltage stays wthin the 
required tolerances/ a modulation control circuit senses the 
output voltage and compares it with a reference voltage* The 
resultant difference from this comparison is used to adjust the 
ON/OFF ratio of the rectangular waveform* The variation off this 
ON/OFF ratio determines the amount of energy that is transferred 
from the primary store to the secondary store(s). 

It is in this way that a Switching Power Supply is able to 
respond to varying load demands without having to dissipate a 
surplus of power as heat* 



«' jqppkz computer inc. 



LtNE 



-TITU 




Fig .4- 



i 



4* ADVANTAGES k DISADVANTAGES OF 3.M.P-. S. 



The basic requirements of m i croprocts sor based equipment and 
other associated applications for pwer supplies are: - 

- the power supply roust produce all the required vol tapes / 
currents within the proscribed tolerances 

- the power supply must be as small as practical 

- the power supply must weigh a little as possible 

- the power supply must be as reliable as possible and produce as 
little heat as possible 

- the power supply must conform to ir meet all the mandatory 
International standards that relate to Safety and Interference 

ADVANTAGES 

Efficiency 



In a linear regulating supply -the power losses are very high* 
This is due to the continuous operation of the series pass 
regulating device* Consequent 1 y > the power efficiency is poor - 
ranging from 10% to 40%> the average being around 30X* 
This figure of 30% means that of tht total power put into the 
power supply only about 30% of it gets to the load - the 
remaining 70X is dissipated in the linear power supply as heat* 
In a Switch Mode Power Supply the device that acts as the 
regulating switch (usually a power transistor) is operated in 
either a fully saturated state or is completely turned off* Since 
the ON and OFF states are the ones of minimum power dissipation 
the power efficiency of a SMPS is much higher and ranges from 65X 
to 80% or more* 



^pppkz computer inc. 



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Figure 5 illustrates the comparison between the power efficiencies 
of linear and SMPS» 




Switch 




Pass* 



This can also be illustrated by looking at a typical power 
supply. For example: - 

For a Power Output of 125 Watts 

Linear power consumption 232 Watts 

SMPS power consumption 54 Watts 



Power saved 



178 Watts 



£cipple computer inc. 



Size & Weight 



Linear supplies taking power from the mains supply work at 50Hz 
(or 60Hz). Since isolation between the input and output is needed 
a transformer is required* The low working frequency dictates 
that the transformer core must be of silicon steel whicti in turn 
results in a component that is both big and heavy. 
SMPS operate at much higher frequencies - typically about 
25/000Hz. This means that the transformer can use ferrife 
materials which are both smaller and lighter than silicon steel* 
An extra benefit is that the efficiency of ferrite in terms of 
magnetic saturation is better than silicon steel which neans that 
the power losses through the transformer are lower for SUPS than 
for linear supplies* 

A further benefit of using high frequency switching that 
contributes to the reduction of size and weight is that the 
secondary electrolytic capacitors can be much smaller* For linear 
supplies it is common to see filter capacitors of 40*00© uF being 
used* SMPS can use i>000 uF capacitors* 

These size and weight advantages can be summarised as f ol I ows : - 
Using the example of a 125 Watt power supply* 



Linear 



SMPS 



Volume comparism 
Area reduction ratio 
Weight reduction ratio 



4 cu in/W 



3.3 



1 cu in/W 



1 



1 



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Opera ting Voltage Range 



Linear supplies tend to have restricted input voltage ranges. 
Often mul t i- tapped transformers are used* This requires the 
equipment end user to set the correct voltage tap according to 
where the equipment is to be used* 

SMPS have very wide operating voltage ranges* Providing the SMPS 
is designed to use primary capacitors sufficient to store the 
energy required even when fed from the low limit of input voltage 
the power supply will continue to function correctly* This is 
because unlike the linear supply the SMPS is not concerned with 
primary volts but only with the energy source* 

The typical operating range of ASTEC SMPS / when set for nominal 
230 V input, is from 180 V to 265 V without need to change' any 
input voltage selector. A comparable range for the nominal 117 V 
setting is also obtained. The change over from nominal 230 V to 
nominal 117 V input setting is achieved by simple altering the 
input rectifier circuit from that of a simple bridge (on 230 V) 
to a voltage doubler (on 117 V) . Thus the resultat DC that is 
used by the switching transistor remains the same for both* input 
voltage ranges. 



We have to accept that SMPS can produce more radiated and/or line 
conducted noise than linear supplies. 

Careful design by ASTEC does reduce both radiated and line 
conducted noise to acceptable amounts* 
Special design features are:- 

Use of special input filters in series with the 
line. These are carefully balanced to obtain the maximum 



DISADVANTAGES 



Noise 



^cippkz computer irtc 



rejection of the switching frequency and its harmonics* 

Pi section filters on the outputs. 

Use of a copper shield between the primary and 
secondary of the power transformer. This acts as an electrostatic 
shield as is connected to the safety ground of the power supply* 

Correct and balanced layout of critical conductors 
on the PCB to ensure that fields cancel « 

Use of another copper shield wound over the 
secondary windings of the power transformer to reduce magnetic 
radia t ion* 

As stated earlier, ASTEC Switching Power Supplies do meet the 
International Standards for both radiated and line conducted 
noise* The most widely specified standards are the VDE0875 and 
VDE0671 and CISPR 1 and 3. 



Trans i en t Response 



Note:- Transient response is the time required for the output 
voltage to return to within the specified regulation limits when 
there is an abrupt change on either the I oad or the line* 
For a conventional linear regulator the figures would be of the 
order of 10's of microseconds* 

For a SMPS these figure are around 10's of milliseconds* 
These times result from the system used and are a function of the 
switching frequency - eventually if we can increase the switching 
frequency sufficiently ( to 10 MHz ) then the response time will 
come down. Meanwhile/ in most practical systems we can live with 
the Transient Response times we get* 



SUMMARY 

The Advantages of the SMPS in terms of Size, Weiqht, Efficiency 
and Reliability more than compensate for the disadvantages* 



popple computer inc. 



5*0 TYPES OF SMPS 



-46- 



There are a number of different ways that a SMPS can be designed* 
There are t wo ma in variants:- 

Fl ybacK Converters 
Feed Forward Converters 

The range of SMPS that ASTEC manufactures mainly use Flyback 
techniques* The Flyback converter is very suitable for power 
supplies up to about 150 Watts. Above this power the Feed Forward 
types tend to predominate. ASTEC make both types but by virtue of 
the number of power supplies in the 50 - 100 Watt range that we 
build the Flyback is the most common circuit solution in our 
current product ion. 

5.1 The Flyback Converter 



Figure 6 shows the basic Flyback circuit and figure 7 shows the 
theorectical waveforms of it*. 

The name 'Flyback'^ is derived from the fact that the energy that 
is stored in the primary winding inductance of the transformer is 
transferred to secondary load during the OFF or 'Flyback' time of 
the switching transistor. 

The circuit operates at a fixed frequency and the period 

the switched ON time ) is varied in order to control the output 

vol tage. 

The switching transistor is in a saturated state ami is 
conducting for the period • The input voltage V*in is 
developed across the primary inductance of the transformer 
causing a linear increase in the primary current. 
The voltage now produced at the secondary is such that the 
rectifier diode is reverse biased. 

At the end of the ON time the primary current reaches a maximum 



^appkz computer inc. 



-47- 




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And cfitppKLrtofK 



LINE 

mpoT 



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Vm.— 



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VOL-rAG;S. 



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value- 12 after wh 1 ch it falls to zero. 

I2 = V. in. £-y 



-48- 



where L is the primary inductance. 
The energy stored in the primary inductance is:- 

2 

L. I 



2 

The stored energy per cycle W is given by:- 

( V. in. £t>2 

W = L ( ) 

- ( L ) 
2 



or 2 2 

V.in . §T - 
W * - 

2L 

Hence the output power available = 

energy in joules x switching frequency 



Therefore: - 



Output Power » 



2 2 
». in,<?T 

2L 



As the primary current falls to zero the voltage across the 
transistor increases from that of its saturation to a positive 
value that is in excess of that of the supply vol tage V.in. A 



capacitive network is connected across the transistor to limit -49 
the rate of rise of this voltage* 

When the voltage across the transistor exceeds V. in, the 
transformer primary is reversed and reverses the secondary 
voltage thus causing the output rectifier diode to conduct* 
An energy recovery winding and a diode limits the voltage across 
the switching transistor and returns the energy stored in this 
inductance to the supply when the circuit is operated without a 
load on the secondary* This winding is bi filar wound with the 
primary in order to minimise the leakage inductance between these 
windings* 

In summary :- 

First: Transistor conducts for a period .(t.on) 

Energy is taken from the input and stored in the inductor* 

Second: During remainder of period <t*off) the output diode 
conducts and the energy stored in the inductor is transferred to 
the output* 

The output voltage is dependent on the input voltage and the 
conduction period of the transistor* 

To stabilise the output voltage the control circui t. determines a 
value for the period appropriate to the input voltage and to 
the loading* 



5*2 The Feed Forward Converter 



Figure S shows the basic circuit* 

The operation of the Feed Forward converter is opposite to that 
of the Flyback converter* 

In the Flyback energy is transferred from primary to secondary 

^oppkz computer inc. 



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-50-. 



during the Or F state of the switching transistor. In the Feed 
Forward energy is transferred during the ON state* 

The smoothing inductor LI in series with the rectifier diode Dl 
provides a voltage that is proportional to the transistor ON 
timet The diode D2 provides the path for the output current when 
the transistor is not conducting. When the transistor is OFF the 
transformer magnetizing current is returned to the supply by an 
energy recovery winding in a similar mode to that of the Flyback 
converter. 






Cortv££-TE:£ Circuit 



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6*0 DATA SHEETS AND SPECIFICATIONS 



-51- 



Our Data Sheets DO contain the answers to most quest ions put by 
potential customers* The purpose of these few notes is to explain 
how to find those answers* 

We have recently started to introduce the 'NewlooK' Data Sheets* 
We will use one of these (AC9231) as an example. 

Front page - the side with the photo 



Between the heavy red lines you will find the basic Volts and 



has the 'negative' outputs floating* This means these can have 
either terminal tied to ground or to another output* The- output 
described as *-i2V could be stacked on top of the +12V output to 
get a +24V output that would then have a current rating of 0*5 
Amp which is the lower of the* two 12V outputs current ratings* 

The rest of the front page is devoted to the mechanical 
dimensions and pin connections* Note that we are getting better 
and giving such details as the mating connector details* 

NO*- WE DO NOT SUPPLY THE MATING PARTS 

Unless we state otherwise; the power supply may be matin-ted in any 
plane* The photo; apart from being pretty is there so that 
engineers can see the internal layout and hence deduce where the 
hot-spots will be i 

The heat producing items are the power transistor* secondary 
diodes, transformer and ripple capacitors* 

Again unless otherwise stated on the Data Sheet we do not expect 
the customer to provide any extra cooling for the power supply - 
normal convection and radiation cooling up to the rated ambient 



Amps 



PLUS 



any special features that the supply 



has* For example* the AC9231 



V 



•'jeippkz computer inc. 



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(usual ly 50 deq. C ) is adequate. 



-52- 



Back Paqe. 



From the top of the paqe to the first heavy red line we show the 
main Vol t/Arnp load data and the line input limits* 

Input Voltaqe:- The min and max fiqures are those between which 
the power supply will stay within the specified output volts for 
all specified output loads* The 9231 will continue to work with 
inputs lower than 180V - in fact it continues down to around 150V 
but we don't spec it down to that level. Above 270V we have a 
marqin for short duration operation - line spikes and such like - 
but not for sustained use. Nowhere in Europe can you find -mains 
supplies that exceed 270 Volts. 

Input Frequency:- We test the supply over the specified ranqe. In 
fact since the input circuit is only a rectifier and capacitor it 
is obvious that the supply can accept a much wider ranqe of input 
frequencies should anyone come up with that requirement. 

Outputs:- The min and max voltaqe of each output is specified as 
is the min and max load* The two specs have to be read toqether. 
For the 9231 +5V output; it means that the volts stay between 4*9 
and 5#1 over the load current ranqe from 6*0 Amps to 1»2 Amps - 
,aqain for any value of line input volts within that spec. 
The minimum load specified may not be the minimum load the power 
supply needs to keep workinq BUT it is the minimum that we 
qaurantee the spec to hold* 

NOTE: - The new family of SMPS have a much better control window 
than the earlier types. This means that the 25X minimum load 
requirement has qone and also it means that the problems of 
trackinq between one output and another are very much less* 

In between the two heavy red lines are the remainder of the 
electrical specifications and notes. 



«' dppkz computer inc. 



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Efficiency:- This is percentage of the input power that can be 
delivered to the load. It will vary with the load. Mostly the 
SMPS will be at its most efficient when delivering the maximum 
power. The figure specified is a minimum - the real typicals are 
nearer to 70% and some units o as high as 75%. 

Operating Temp:- When we say 'Ambient' we mean the ambient around 
the power supply not that around the equipment that houses the 
power supply. 

Output Power:- This is the max continuous power that can be 
drawn. It is the sum of all the loads. If you sum the VA products 
on each of the outputs it is higher than 50 Watts because the 
practical case is that although higher currents may be needed on 
the +5 and +12 the demand does not occur at the same time. 

Output Ripple:- This is measured with a Wideband instrument 
across the output terminals. We specify it as a percentage of the 
output voltage on each given output rail. Thus for the 9231 it 
mean£ a max ripple figure of 50mV on the +5V rail and 120mV on 
the +12V one. In both cases these are peak-to-peak figures. The 
best instrument for measuring Ripple is a 'scope which has a 
sui tab 1 e bandwidth* 

Line regulation:- This defines the variation in the output 
voltages over the line input range - thus the +5V could change by 
+/- 0*2% ; or iOmV for a line input change from 180V to 270V. 

Load regulation:- This defines the variation in the output 
voltages over the whole of the specified load range. Thus for the 
+ 5V output it means that it may vary by 2»0X f or lOOmV when the 
load changes from 6.0 A to 1.2 A. If you look at the 'Outputs' 
specs above it may look as though there is a 200mV variation 
possible due to load but this is not so. Due to load the 
variation is lOOmV - the other lOOmV is the variation in the 
absolute value of the + 5V output. 

Over Voltage Protection:- The main output lines have crowbar 



^cippkz computer inc. 



-54 



circuits to protect equipment connected to the power suppfy in 
the event of a total failure in the control circuits. The crowbar 
firing voltaqe is specified in this >.uav« 

Hold up Time:- This is the time for which the power supply will 
continue to deliver power after the mains input has failed* The 
specification refers to the line input voltage - normally we spec 
at the nominal line input but for maximum load which is a worst 
case condition* The hold-up time extends until the output voltaqe 
has fallen outside the rated tolerance* 

The remainder of this section deals with any special points* For 
exampe the note about the max voltage that can occur between the 
'floating' outputs on the AC9231* 

Most of our SMPS will stand indefinite short circuit and open 
circuit load conditions. Short circuits are defined as being less 
than 50 m ohms* For the power supplies of 150 W ratinas or more 
we have to incorporate secondary fuses since it is possible in 
the 'prac t ica 1 case to have a 'short' circuit that is not a real 
short at all* The power supply sees it as a very low impedance 
load and tries to deliver all the power into one output* Mithout 
the secondary fuse as protection there could occur a failure of 
the secondary diodes* This case is not applicable to such units 
as the Ac9231. 

Notes on applicable Safety specs and EMI and radiated Noise specs 
are 'also given* 

In general we are complying with all the European safety 
standards* Transformer design complys with the construction 
tecniques specified/ PCB layout conforms to the required 
spacings* Materials conform to both European and UL/CSA needs* 

Further details on these matters are available from us for 
specific customers if needed* 

«'jcippkz computer inc. 



TARGET M.T.B.F. — 100,000 HOURS! 



SUf/MARlSED MANUFACTURING PROCESS 



< 

d 

2 
tu 
2 
O 

Ql 

2 
O 
u 



COMPONENT IOC 



T 



ATTACH TRACE NUMBER 



T 



100% COMPONENT TEST 



I 



10 THERMAL CYCLES 



T 



24 - 96HRS. BURN-IN 



I 



100% TEST 



SUBASSEMBLY 



T 



TRACE NUMOLH LOGGLD 
AGAINST SERIAL NO. 



T 



1 6 STEP COMPUTE R TEST 
1 ~ 



10 THERMAL CYCLES 



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24 - 96HRS. BURN IN 



16 STEP COMPUTER TEST 



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PACKING 



STORE 



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This chart details the step by step procedures 
taken by ^STEC to ensure that the final 
product has reliability-built in. 



All critical components, semi conductors and 
capacitors, are tested before and after pre- 
assembly burn-in. Comparison of test results 
enables us to eliminate any suspect compo- 
nents before assembly starts. 



The assembled power supply is then computer 
tested, the test results stored, mn up uiufei 
worst case input conditions and with maxi- 
mum rated loads for 96 hours and then 
re- tested. 



Comparison of test results enables us to reject 
any units showing parameter changes likely to 
cause failures during use. 



It is our target to offer a power supply that 
system designer can specify with absolute 
confidence, can fit and can then forget. The 
name ASTEC is synonymous with quality 
and reliability. 



gcippkz computer inc. 



SWITCHING POWER SUPPLIES 



Editors note: The material for this article 
was edited from HP's DC Power Supply 
Handbook (AN 90B), originally written 
by Richard Tomasetti of the Marketing 
Communications group at HP's power 
supply division in Rockaway, New 
Jersey, 

Electronic power supplies are de- 
fined as units that convert power 
from an ac or dc source into ac or dc 
power at voltages suitable for sup- 
plying an electronic device. 

Within this definition, electronic 
power supplies can be divided into 
four broad classifications: 

(1) ac in, ac out — line regu- 
lators and frequency changers 

(2) dc in, dc out — converters 
and dc regulators 

(3) dc in, ac out — inverters 

(4) ac in, dc out — "common" 
power supply 

This last category is by far the most 
common of the four and is generally 
the one referred to when speaking of 
a "power supply." 

Four basic outputs or modes of 
operation can be provided by dc out- 
put power supplies: 

• Constant Voltage: The output 
. voltage is maintained constant in 

spite of changes in load, line, or 
temperature. 

• Constant Current: The output 
current is maintained constant in 
spite of changes in load, line, or 
temperature. 

• Voltage Limit: Same as Constant 
Voltage except for less precise 
regulation characteristics. 

• Current Limit: Similar to Con- 
stant Current except for less pre- 
cise regulation. 

Within each type of power supply, 
different forms of regulation are 
used to maintain a constant output. 
Switching is one of the forms used in 
a constant voltage power supply. 



Therefore, a switching power 
supply is defined as an ac in, dc 
out, constant voltage power sup- 
ply that uses a "switching tech- 
nique" for regulation. 



Basic SwiteMng Supply 

In a switching supply, the regulat- 
ing elements consist of series- 
connected transistors that act as 
rapidly opened and closed switches 
(Figure 1). The input ac is first con- 
verted to unregulated dc, then 
"chopped" by tHe switchihe "element 
operating at a rapid rate (typically 
20kHz). The resultant ZUkflz pulse 
tratrris transformer-coupled to an 
output network which provides final 
rectification and smoothing of the dc 
output. Regulation is accomplished 
through control circuits that vary 
the on-off periods (duty cycle) of the 
switching elements. 



2 .„ -* nwtf. , — «twTinf«»iiTr«.-«. 

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Figure 1. Basic Switching Supply 



Operating Advantages. Because 
switching regulators are basically 
on/off devices, they avoid the higher 
power dissipation associated with 
the rheostat-like action of a series 
regulator. The switching transistors 
dissipate very liftle power when 
either saturated (on ) or nonconduct- 
ing (off); most of the power losses 
occur elsewhere in the supply. Ef- 
ficiencies ranging from 65% to 85% 
are typical for switching supplies, as 
compared to 30% to 45% efficiencies 
for linear types. With less w r asted 
power, switching supplies run at 
cooler temperatures, cost less to op- 
erate, and have smaller regulator 
heat sinks. 




r 



— \ 

-57- 



The size and weight reductions for 
switching supplies are achieved be- 
cause of their high switching rate. 
The power transformer, inductors, 
and filter capacitors for 20kHz 
operation are much smaller and 
lighter than those required for 
operation at power line frequencies. 
Typically, a switching supply is less 
than one-third size and weight of a 
comparable series regulated supply. 

Another aspect of performance is the 
switcher's ability to operate under 
low ac input voltage (brownout) con- 
ditions and substain a relatively 
long carryover (or holdup) of its out- 
put if input power is lost momentar- 
ily. The switching supply is superior 
to the linear supply in this regard 
because more energy is stored in its 
input filter capacitance. In a switch- 
ing supply, the input ac is rectified 
directly and the filter capacitor 
charges to the voltage peaks on the 
ac line. This is opposed to the linear 
supplies' ac input being stepped 
down through a power transformer, 
then rectified, which results in a 
lower voltage across its filter 
capacitor. 

Since the energy stored in a 
capacitor is proportional to CV2, and 
V is higher in switching supplies, 
their storage capability (and thus 
their holdup time) is better. 

Operating Disadvantages. Al- 
though its advantages are impres- 
sive, a switching supply does have 
some inherent operating charac- 
teristics that could limit its 
effectiveness in certain applications. 
One of these is that its transient re- 
covery time (dynamic load regula- 
tion) is slower than that of a series 
regulated supply. In a linear supply, 
recovery time is limited only by the 
speeds of the semiconductors used 
in the series regulator and control 
circuitry. However, in a switching 
supply, recovery is limited mainly 
by the inductance in the output fil- 
ter. This may or may not be of sig- 
nificance to the user, depending 
upon the specific application. 



Alsck electro-magnetic interference 
(EMI) is a natural by-product of the 
on-off switching. This Interference 
can be conducted to the load (result- 
ing in higher output ripple and 
noise), it can be conducted back into 
the ac line, and it can be radiated 
into the surrounding atmosphere. 

For this reason, all Hewlett- 
Packard switching supplies have 
built-in shields and filter networks 
that substantially reduce EMI and 
control output ripple and noised 

Typical Switching Regulated 
Power Supply 

Figure 2 shows a schematic of one of 
HP's higher power, yet less com- 
plex, switching supplies. Regulation 
is accomplished by a pair of push- 
pull switching transistors operating 
under control of a feedback network 
consisting of a pulse-width mod- 
ulator and a voltage comparison 
amplifier. The feedback elements 
control the ON periods of the 
switching transistors to adjust the 
duty cycle of the bipolar waveform 
(E) delivered to the output rectifier/ 
filter. Here the waveform is rectified 
and averaged to provide a dc output 
level that is proportional to the duty 
cycle of the waveform. Hence, in- 
creasing the ON times of the 
switches increases the output volt- 
age and vice-versa. 

The waveforms of Figure 2 provide 
a more detailed picture of circuit 
operation. The voltage comparison 
amplifier continuously compares a 
fraction of the output voltage with a 
stable reference (Eref) to produce 
the VCONTROL level for the turn-on 
comparator. This device compares 
the V CONTROL input with a triangu- 
lar ramp waveform (A) occurring at 
a fixed 40kHz rate. When the ramp 
voltage is more positive than the 
control level, a turn-on signal (B) is 
generated. Notice that an increase 
or decrease in the VCONTROL volt- 
age varies the width of the output 
pulses at B and thus the ON time of 
the switches. 





Figure 2. Switching Supply with Push-Pull Transistor* and Feedback for Regulation 



Steering logic within the modulator 
chip causes switching transistors 
Ql and Q2 to turn on alternately, so 
that each switch operates at one- 
half the ramp frequency or 20kHz. 

Included, but not shown, in the 
modulator chip are additional cir- 
cuits that establish a minimum 
"dead-time" (off time) for the 
switching transistors. This ensures 
that both switching transistors can- 
not conduct simultaneously during 
maximum duty cycle conditions. 

Ac Input Surge Current Protec- 
tion. Because the input filter 
capacitors are connected directly 
across the rectified line, some form 
of surge protection must be provided 
to limit line surge currents at 
turn-on. If not controlled, large 
surges could trip circuit breakers, 
weld switch contacts, or affect the 
operation of other equipment con- 
nected to the same ac line. Protec- 
tion is provided by a pair of ther- 
mistors (Rt°) in the input rectifier 
circuit. With their high negative 
temperature coefficient of resist- 
ance, the thermistors present a 
relatively high resistance when cold 
(during the turn-on period) and a 
very low resistance after they 
heat up. 

A shorting strap (Jl) permits the 
configuration of the input rectifier- 
filter to be altered for different ac 
inputs. For a 174-250Vac input, the 
strap is removed and the circuit 
functions as a conventional full- 
wave bridge. For 87-127Vac inputs, 
the strap is installed and the input 
circuit becomes a voltage doubler. 



Switching Frequencies. Pre- 
sently, 20kHz is a popular repeti- 
tion rate for switching regulators 
because it is an effective com- 
promise with respect to size, cost, 
dissipation, and other factors. De- 
creasing the switching frequency 
would bring about the return of the 
acoustical noise problems that 
plagued earlier switching supplies, 
and would increase the size and cost 
of the output inductors and filter 
capacitors. 

Increasing the switching frequency, 
however, would result in certain 
benefits, including further size re- 
ductions in the output magnetics 
and capacitors. Furthermore, tran- 
sient recovery time could be de- 
creased because a higher operating 
frequency would allow a propor- 
tional decrease in the output induct- 
ance, which is the main constraint in 
recovery performance. 

Unfortunately, higher frequency 
operation has certain drawbacks. 
One is that filter capacitors have an 
Equivalent Series Resistance (ESR) 
that limits their effectiveness at 
high frequencies. Another disad- 
vantage is that power losses in the 
switching transistors, inductors, 
and rectifier diodes increase with 
frequency. To counteract these 
effects, critical components such as 
filter capacitors with low ESRs, fast 
recovery diodes, and high-speed 
switching transistors are required. 



^cippkz computer inc. 



Some of these components are al- 
ready available, others are not. 
Switching transistors are improv- 
ing, but remain one of the major 
problems at high frequencies. How- 
ever, further improvements in 
high-speed switching devices, such 
as the new power Field Effect Tran- 
sistors (FETs) would make high fre- 
quency operation and its associated 
benefits a certainty for future 
switching supplies. 

Preregulated Switching Supply 

Figure 3 shows a schematic of 
another switching supply similar to 
Figure 2 except for the addition of a 
triac preregulator and associated 
control circuit. The triac is a 
bidirectional device and is usually 
connected in series with one side of 
the input primary. Whenever a gat- 
ing pulse is received, the triac con- 
ducts current in a direction that is 
dependent on the polarity of the 
voltage across it. The goal is to con- 
trol the triac so that the bridge rec- 
tifier output (dc input to the 
switches) is held relatively con- 
stant. This is accomplished by a 
control circuit that issues a phase- 
adjusted firing pulse to the triac 
once during each half-cycle of the 
input ac. The control circuit com- 
pares a ramp function to a rectified 
ac sinewave to compute the proper 
firing time for the triac. 

Although the addition of the pre- 
regulator circuitry increases com- 
plexity, it provides three important 
benefits. 

(1) By keeping the dc input to the 
switches constant, it permits 
the use* of more readily avail- 
able lower voltage switching 
transistors. 

(2) The coarse preregulation it pro- 
vides allows the main regulator 
to achieve a finer regulation. 

(3) Through the use of slow-start 
circuits, the initial conduction of 
the triac is controlled, providing 
an effective means of limiting 
input surge current. 

Note that the preregulator triac is 
essentially a switching device and, 
like the main regulator switches, 
does not absorb a large amount of 
power. Hence, the addition of the 
preregulator does not significantly 
reduce the overall efficiency of this 
supply. 



Single Transistor Switching 
Regulator 

At lower output power levels, a one- 
transistor switch becomes practical. 
The single transistor regulator of 
Figure 4 is referred to as a forward, 
or feed-through, converter. It can re- 
ceive a dc input from either one of 
two sources without a change in its 
basic configuration. For ac-to-dc 
requirements, the regulator is con- 
nected to a line rectifier and SCR 
preregulator. For dc-to-dc converter 
applications it is connected directly 
to an external dc source. 

Like the previous switching 
supplies, the output voltage is con- 
trolled by varying the ON time of 
the regulator switch. The switch is 
turned on by the leading edge of 
each 20kHz clock pulse and turned 
off by the pulse-width modulator 
at a time determined by output load 
conditions. 

While the regulating transistor is 
conducting, the half-wave rectifier 
diode is forward biased and power is 
transferred to the output filter and 
the load. When the regulator is 
turned off* the "flywheel" diode con- 
ducts, sustaining current flow to the 
load during the off period. A 
flywheel diode (sometimes called a 
freewheeling or catch diode) was 
not required in the two transistor 
regulators of Figures 2 and 3 be- 
cause of their full-wave rectifier 
configuration. 

Another item not found in the previ- 
ous regulators is "flyback" diode 
CRF. This diode is connected to a 
third transformer winding which is 
bifilar wound with the primary. 
During the off periods of the switch, 
CRF is forward biased, allowing the 
return of surplus magnetizing cur- 
rent to the input filter, and thus pre- 
venting saturation of the trans- 
former core. This is an important 
function because core saturation 
often leads to the destruction of 
switching transistors. In the previ- 
ously described two transistor 
push-pull circuits, core saturation is 
easier to avoid because magnetizing 
current is applied to the core in both 




AC 
IN 



PREREWlATOR 
TRlAC 



Lx 




PRE REG 
CONTROL 
CUT 



REGULATOR 
" SWITCHES " 



■i 



PRtRIG 
OUTPUT 

I 



OF 



MOD 



PULSE 
WIDTH 
MODULATOR 
CKTS 



n 



TURK -ON 
COMPARATOR 



OC 
OUT 




VOLTAGE 
COMP 
AUPL 



Figure 3. Push-Pull Switching Supply with Triac PreregaUtor 




Figure 4. Single Transistor Switching 
Regulator called a Forward or 
Feed-Through Converter 



directions (i.e., before saturation, 
the current is reversed). Neverthe- 
less, matched switching transistors 
and balancing capacitors must still 
be used in these configurations to 
ensure that core saturation does not 
occur. 

Configuration B is a useful alterna- 
tive to push-pull operation for lower 
power requirements. It is called a 
forward or feed-through converter 
because energy is transferred to the 
power transformer secondary im 
mediately following turn-on of the 
switch. Although the ripple fre- 
quency is inherently lower, outpui 
ripple amplitude can be effective]} 
controlled by the choke in the outpu* 
filter. Two-transistor configuration; 
of forward converters also exis 
wherein both transistors an 
switched simultaneously. They pro 
vide the same output power as th. 
single transistor versions, but th» 
transistors need handle onlv half tb 
peak voltage. 



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Figure 5. Summary of Basic Switching 
Regulator Configurations 



Summary ©f Basic Switching 
Regulator Configurations 

Figure 5 shows three basic switching 
regulator configurations that are 
often used m today's power supplies. 
Configuration A is of the push-pull 
class, and His version was used in 
the switching supplies shown in 
Figures 2 ami 3. Other variations of 
this circuit are used also, including 
two-transista* balanced push-pull 
and four transistor bridge circuits. 

As a group, push-pull configurations 
are the m@st effective for low- 
voltage, high-power and high per- 
formance applications. Push-pull 
circuits haw the advantage of a rip- 
ple frequency that is double that of 
the other two basic configurations 
and, of comrse, output ripple is 
inherently lower. 



Ripple mnputar inc. 



r 



— \ 

-61- 



Configuration C is known as a 
flyback, or ringing choke, converter 
because energy is transferred from 
primary to secondary when the 
switches are off (during flyback). In 
the example, two transistors are 
used and both are switched simulta- 
neously. While the switches are on, 
the output rectifier is reverse biased 
and current in the primary induct- 
ance rises in a linear manner. 
When the switches are turned off, 
the collapsing magnetic field re- 
verses the voltage across the pri- 
mary, and the previously stored en- 
ergy is transferred to the output fil- 
ter and load. The two diodes in the 
primary protect the transistors from 
inductive surges that occur at turn- 
off. 

Flyback techniques have long been 
used as a means of generating high 
voltages (e.g., the high voltage 
power supply in television receiv- 
ers). As you might expect, this con- 
figuration is capable of providing 
higher output voltages than the 
other two methods. Also, the flyback 
regulator provides a greater varia- 
tion of output voltage with respect to 
changes ift duty cycle. Hence, the 
flyback configuration is the most ob- 
vious choice for high, and variable 
output voltages while the push-pull 
and forward configurations are more 
suitable for providing low, and fixed 
output voltages. 



Protection Circuits for Switching 
Supplies 

Figure 6 shows typical protection 
circuits that are used in HP switch- 
ing regulated power supplies. The 
following is a brief description of 
those protection circuits shown. 

A. EMI Filter. Helps prevent high 
frequency spikes (RFI) from being 
conducted to the load or back into 
the ac line. HP switching supplies 
also contain built-in shields for addi- 
tional control of conducted and 
radiated interference. 



Has a high resistance when cold 
(during turn-on) and low resistance 
after it heats up. 

C. Regulator Overcurrent Limit. 
This circuit is much faster than the 
current limit comparator and pro- 
tects the regulator switches from 
overcurrent conditions of a transient 
nature. It monitors current flow 
through the switches and prevents it 
from exceeding a harmful level. 

D. Output Rectifier Diodes. Be- 
sides final rectification, these diodes 
also protect internal components 
against reverse currents that could 
be injected into supply by an active 
load or series connected supply. 

E. AC Undervoltage. This circuit 
performs a dual function. It protects 
the supply from damage that could 
result from a prolonged condition of 
low ac input voltage, and it limits 
output overshoot during turn-on. 
During undervoltage or turn-on 
conditions, the low ac input level re- 
duces the V B j AS voltage and acti- 
vates the undervoltage detector. 
When activated, the modulator 
pulses are inhibited and the reg- 
ulator switches turned off. 

F. Overvoltage Detector. Monitors 
output voltage and turns off reg- 
ulator switches if output attempts to 
rise above a preset value. Similar to 
a crowbar circuit except that output 
voltage is removed by turning off 
regulator rather than by shorting 
the output. 



G. Temperature Switch. Opens in 
case of high ambient temperature 
thai could be caused, for example, by 
a misapplication or cooling fan fail- 
ure. The switch opens and removes 
VBIAS which activates the ac vnder- 
voltage detector. The switch closes 
again after temperature cools to a 
safe level. 



B. Thermistor. Limits ac input 
surge current by its negative tern- 
perature coefficient of resistance. 




-62- 




Figure 6. Protection Circuits, Switching Type Supply 



SWITCHING SUPPLY TERMINOLOGY 



The following is a brief glossary of 
terms encountered in dealing with 
switching supplies. 

Brown Out Rated 

The ability of a power supply to 
maintain regulated output voltages 
in the event that the input line volt- 
age should drop to a low or zero 
level. 



FOLDBACK 



COfcSUtfT VOI TACf 

CKCSSOVEft 




Current Foldback 

An overload protection method 
where output voltage and current 
decrease simultaneously as the load 
resistance decreases below a preset 



crossover point and begins to ap- 
proach a short circuit. Also known as 
output short circuit protection, this 
mechanism monitors the output cur- 
rent and, if it exceeds a preset cross- 
over value, turns down the regulator 
output. 

EMI (RFI) 

Electromagnetic interference (radio 
frequency interference) — unwanted 
high frequency energy caused 
primarily by the switching compo- 
nents in the power supply. EMI can 
be conducted through the input or 
output lines or radiated through the 
unit's case. Conducted EMI (RFI) 
can be reduced using proper filter- 
ing, and radiated EMI (RFI) can be 
reduced by judicious board layout 
and enclosing the supply in a metal 
enclosure. 

The terms "noise" EMI and RFI are 
sometimes used in the same context. 




ESR (Equivalent Series 
Resistance) 

The amount of resistance in series 
with an ideal (lossless) capacitor 
which exactly duplicates the per- 
formance of a real capacitor. In gen- 
eral, the lower the ESR, the better 
the quality of the capacitor and the 
more effective it is as a filtering 
device. ESR is a prime determinant 
of ripple in switching supplies. 

Flyback 

Precisely, it's the shorter of the two 
time intervals comprising a saw- 
tooth wave. In a switching power 
supply, the shorter interval is pro- 
duced when the transistors are 
switched off. This causes a rapidly 
collapsing magnetic field in the 
transformer which reverses the 
voltage across the primary, transfer- 
ring a high energy to the output. 

Ground Loop 

A feedback problem caused by two or 
more circuits sharing a common 
electrical line, usually a common 
ground line. Voltages gradients in 
this line caused by the first circuit 
may be resistively, inductively, or 
capacitively coupled into the other 
circuit via the common line. With 
power supplies, this problem can be 
reduced using single point ground- 
ing near the supply. 



Isolation Voltage 

The maximum voltage by which any 
part of the circuit can be operated 
away from chassis ground. Also the 
maximum voltage between any out- 
put and input terminal. 

Line Regulation 
See Source Effect. 

Line Frequency Regulation 

The variation of an output voltage 
due to a change in line input fre- 
quency with all other factors held 
constant. This effect is negligible in 
switching and most linear supplies, 
but is very critical in ferroresonant 
supplies. 

Load Effect Transient Recovery 
Time 

Sometimes referred to as transient 
recovery time or transient response 
time, it is, loosely speaking, the time 
required for the output voltage of a 
power supply to return to within a 
level approximating the normal dc 
output following a sudden change in 
load current. More exactly, Load 
Transient Recovery Time for a CV 
supply is the time "X" required for 
the output voltage to recover to, and 
stay within "Y" millivolts of the 
nominal output voltage following a 
ff Z" amp step change in load current 
— where: 



Hold-up Time 

The total time any output will 
remain within its regulation band 
after line input voltage has suddenly 
dropped to zero or below rating. 
Hold-up is measured at full load and 
nominal line conditions. 



Input Surge Current 

The peak line current which flows 
during turn-on. Surge current is 
caused by charging of the input 
capacitor, and limited primarily by 
an input thermistor or preregulator. 

Input Voltage Range 

The range of line voltages for which 
the power supply meets its specifica- 
tions. The lowest line voltage is im- 
portant in defining the relative de- 
gree of brown-out protection. 



(1) "Y" is specified separately for 
each model, but is generally of 
the same order as the load 
regulation specification. 

(2) The nominal output voltage is 
defined as the dc level half- 
way between the steady state 
output voltage before and 
after the imposed load 
change. 

(3) "Z" is the specified load cur- 
rent change, typically equal 
to the full load current rating 
of the supply. 




TRANSIENT RECOVERY TIME 



'OUT 



NO 



FULL LOAO 
LOAO 



LOAO CURRENT 



u 

Y 



L 



NOMINAL OUTPUT 
VOLTAGE 



VOLTAGE RECOVERY 



Overcurrent Limiting 



PARD (Ripple and Noise) 

The term PARD is an acronym for 
"periodic and random deviation" and 
replaces the former term ripple and 
noise. PARD is the residual ac com- 
ponent that is superimposed on the 
dc output voltage or current of a 
power supply. It is measured over a 
specified bandwidth with all influ- 
ence and control quantities main- 
tained constant. PARD is specified 
in rms and/or peak-to-peak values 
over a bandwidth of 20Hz to 20MHz. 
Fluctuations below 20Hz are treated 
as drift. Attempting to measure 
PARD with an instrument that has 
insufficient bandwidth may conceal 
high frequency spikes that could be 
detrimental to a load. 



A protection mechanism which lim- 
its the output current of a supply 
without materially affecting the 
output voltage. 

Overshoot 

The amount by which an output ex- 
ceeds its final value in a transient 
response to a rapid change in load or 
input voltage. In power supply de- 
sign this parameter is particularly 
important at turn-on. 



DC OUTPUT OF POWER SUPPLY 
AND SUPERIMPOSED PARD 
COMPONENT 



Overvoltage Protection 

A protection mechanism for the load 
which reduces the output voltage to 
a very low value in the event that 
the output exceeds a certain 
threshold voltage. In a switching 
supply, the regulator is turned off if 
the threshold is exceeded, reducing 
the output voltage and current to 
zero. In linear supplies, an SCR 
"crowbar" is used to rapidly place a 
short circuit across the output ter- 
minals whenever the threshold volt- 
age is exceeded. 



Peak Charging 

A rise in voltage across a capacitor 
caused by the charging of the 
capacitor to the peak rather than 
RMS value of the input voltage. This 
generally occurs when a capacitor 
has a high discharge resistance 
across it and large ripple or spikes on 
its input line. In a switcher this effect 
determines minimum load (dis- 
charge resistance) conditions on each 
output to maintain regulation. 



£cippkz computer inc. 



r 



-65- 



Post Regulator 

A linear »dissipative) regulator used 
on the output of a switching supply 
to further improve over-all regula- 
tion performance of the supply. Post 
regulators can be either the 3 termi- 
nal I.C. type or a custom discrete 
design. Since the differential voltage 
across the post regulator can be kept 
to a minimum, dissipative losses are 
generally small. 



Rise Time and Fall Time 

When applied to the switching tran- 
sistor, that time in which- non-zero 
currents and voltages result in high 
peak power dissipation. Careful at- 
tention must be paid to reducing 
these times, particularly when 
switching inductive loads. 

Ripple and Noise 
See PARD. 

Short Circuit Protection 
See Current Foldback. 



Source Effect (Line 
Regulation) 

Formerly known as line regulation, 
source effect is the change in the 
steady-state value of the dc output 
voltage (of a CV supply) or current 
(of a CC supply) due to a specified 
change in the source (ac line) volt- 
age, with all other influence quan- 
tities maintained constant. Source 
effect is usually measured after a 
"complete" change in the ac line 
voltage from low line to high line or 
vice-versa. 

Switcher 

A common industry-wide name for a 
switching power supply. 

Temperature, Coefficient 

The average percent change in out- 
put voltage per degree change in 
temperature with load and input 
voltage held constant. The coeffi- 
cient is usually derived from output 
voltage measurements taken at 
room temperature (25°C) and at the 
two specified operating temperature 
extremes.